Potential for homosexual response is prevalent and genetic.
"We investigated the potential to engage in
homosexual behavior in 6001 female and 3152 male twins and their siblings finding that 32.8% of the men and 65.4% of the women reported such potential (p<0.001). 91.5% of these men and 98.3% of these women reported no overt
homosexual behavior during the preceding 12 months. The potential to engage in
homosexual behavior was influenced by genetic effects for both men (37.4%) and women (46.4%) and these overlapped only partly with those for overt
homosexual behavior."
Please note that in addition to referring to homosexuality as a behavior, it also contradicts the idea that it is not learned or learnable. Homosexual potential is widespread, but the behavior itself is limited. In cases where some genetic influence was recognized, even then only a portion of gays had the genetic influence, and many who were not gay had the genetic influence but still behaved heterosexually.
So both from the purely linguistic and even from the sense of attraction, there appears to be no support for the idea that the scientific community is of one mind that the phrase, "homosexuality is a behavior," is somehow unscientific or inaccurate.
Homosexuality can be described in terms of both desire and behavior. I don't think the phrase "homosexuality
is a behavior" is accurate, though.
Jim is only sexually attracted to woman. Through a series of misfortunes he finds himself living on the streets, where he learns there are very lucrative opportunities for male prostitutes who service wealthy business men. He becomes such a prostitute and continues doing it for a while because it pays well, even though he gets no sexual pleasure from it. Is he gay?
Stanley is only sexually attracted to men. He's very embarassed by it, however, and desperately wants to be "normal". As a result, he only dates women and ends up marrying Jill. They are married for several years even though he fantasizes about men every time he is intimate with her. He loves Jill as a person, but feels no romantic attraction to her or any other woman. In fact, he has a crush on a male coworker, although he would never tell anyone his secret. Is he straight?
Here's an analogy for ya (and true story

) I have never been good at math. As a kid in school I always excelled in reading and writing courses, and struggled with numbers. It just never came naturally to me like it did for some other students, and I didn't enjoy doing it at all. That doesn't mean I couldn't push my way through it -- and I did. I had an excellent math teacher in high school and ended up taking calculus as a junior, and advanced calculas / quadratics as a senior. Did I like it? Nope. Did it ever become easy for me? Nope. I just did it because I knew I needed it to get in to college ... where I dropped it as quickly as I could in favor of the social sciences and humanities which I enjoyed and continued to excel at.
I think of homosexuality in much the same way. People are born with proclivities. Does this mean a gay man can't have sex with a woman? No. Does it mean that he can't try to explore or develop that side of himself that may be attracted to women? No. Does that mean such an exploration will change how he feels about women ... or men? Maybe, maybe not. I'm pretty sure that all the math tutors in the world couldn't make me a mathematician -- or, at least, they could never make me better at numbers than I am with words. It's just not me. I don't have an inner Pythagorus, and if I was forced to look for it rather than be allowed to go with what I'm naturally good at I think I'd be pretty miserable.
Similarly, I think there are bisexuals out there (i.e., those who are somewhere in between a 1 and a 6 on the Kinsey scale) who can probably consciously or subconsciously suppress the side of themselves that is attracted to the same sex. But the question is why should they feel forced to do so?
Why would you try to force someone who is a gifted writer that is primarily or exclusively attracted to the same sex to be a heterosexual accountant? It just doesn't make any sense.
I guess you'd first have to buy into the idea that it is bad to be homosexual, and for those of us who disagree, this seems like nothing but a mean spirited exercise in frustration.